Textures: prevent assert/crash of having a destroyed texture recreated without the pixels data available (#9150, #8811)

Amend 8c22b8a

Author: sammyfreg

imgui.h

@@ -3509,7 +3509,7 @@ struct ImTextureData
     // - Call SetTexID() and SetStatus() after honoring texture requests. Never modify TexID and Status directly!
     // - A backend may decide to destroy a texture that we did not request to destroy, which is fine (e.g. freeing resources), but we immediately set the texture back in _WantCreate mode.
     void    SetTexID(ImTextureID tex_id)            { TexID = tex_id; }
-    void    SetStatus(ImTextureStatus status)       { Status = status; if (status == ImTextureStatus_Destroyed && !WantDestroyNextFrame) Status = ImTextureStatus_WantCreate; }
+    void    SetStatus(ImTextureStatus status)       { Status = status; if (status == ImTextureStatus_Destroyed && !WantDestroyNextFrame && Pixels != nullptr) Status = ImTextureStatus_WantCreate; }
 };
 
 //-----------------------------------------------------------------------------